Morphogenesis of Malus domestica cv. Starking flower buds

Abstract

Differentiation of reproductive buds of the Starking apple (Malus domestica) was studied by scanning electron microscopy. Differentiation of reproductive structures was initiated during the first week of January when the shoot apex flattened. In terminal flower primordia, sepal primordia were evident in the second week of January, petal and stamen primordia from the end of January to mid-February and carpel primordia in mid-February. Floral organs developed slowly from March to August and pollen sacs were only formed in the anthers at the end of this period. Development accelerated during September and ovules formed three weeks before full bloom. The carpels rapidly increased in length and fused with the receptacle at their dorsal ends. The inner and outer integuments of the ovule developed and the filaments of anthers lengthened rapidly during the last three weeks before full bloom.